308win: 178gr hpbt, PP2000mr, and 16.5" barrel...

[InkedIan]

Well I started pressure tests for some new loads. Here's specs:
Savage 12/10 with a factory 1-10" heavy barrel shortened to 16.5"
178gr Hornady HPBT Bullets
PP2000MR Powder
CCI 200 LR primers
Hornady 308win match brass

I started high but got good results! Theses are just 4 shot averages not single shot velocities.
48grs: 2720 no pressure signs
48.4grs: 2742 slight pressure signs
48.8grs: 2779 mild pressure signs
49.2grs: 2802 obvious pressure signs

Hopefully this weekend i'll get to do some accuracy testing. I'll be loading from 47.2grs to 48.6grs in .2gr increments 5 shots per load. I'll let y'all know the results

 

[Pusher591]

Well I started pressure tests for some new loads. Here's specs:
Savage 12/10 with a factory 1-10" heavy barrel shortened to 16.5"
178gr Hornady HPBT Bullets
PP2000MR Powder
CCI 200 LR primers
Hornady 308win match brass

I started high but got good results! Theses are just 4 shot averages not single shot velocities.
48grs: 2720 no pressure signs
48.4grs: 2742 slight pressure signs
48.8grs: 2779 mild pressure signs
49.2grs: 2802 obvious pressure signs

Hopefully this weekend i'll get to do some accuracy testing. I'll be loading from 47.2grs to 48.6grs in .2gr increments 5 shots per load. I'll let y'all know the results


View attachment 10998View attachment 10999

No offense at all but I just can't believe that. For those charges and that barrel length, I've never seen those velocities, not personally or posted online. I'm not saying your lying, I'm just saying I don't think your chrono is giving an accurate reading. From what I've seen, those velocities are common with the longer barrels and 2000MR but I just don't think the laws of physics can allow 175/178 grain bullet to reach that speed from that length of barrel. It would be cool if I was wrong and please keep us posted if the dope matches the velocity given.

 

[InkedIan]

No offense at all but I just can't believe that. For those charges and that barrel length, I've never seen those velocities, not personally or posted online. I'm not saying your lying, I'm just saying I don't think your chrono is giving an accurate reading. From what I've seen, those velocities are common with the longer barrels and 2000MR but I just don't think the laws of physics can allow 175/178 grain bullet to reach that speed from that length of barrel. It would be cool if I was wrong and please keep us posted if the dope matches the velocity given.

Well, i'm just posting chrony readings and I've used it's readings for 1000+yd steel matches so I have reason to believe it's accurate. Ummm, idk what else to say other than that.... If I get different readings when I do accuracy testing i'll post'em regardless of the result.

 

[Pusher591]

Just noticed you are running a suppressor. My own personal experience I've seen higher then average free bore boost numbers on shorter barrels. You number might not be that far off.

I had a 17.5" barreled gun that routinely saw a 40-60 fps free bore boost when running suppressed. Same suppressor on my buddies 20" gun only increased the velocities 20 fps.

 

[thespecialist]

No offense at all but I just can't believe that. For those charges and that barrel length, I've never seen those velocities, not personally or posted online. I'm not saying your lying, I'm just saying I don't think your chrono is giving an accurate reading. From what I've seen, those velocities are common with the longer barrels and 2000MR but I just don't think the laws of physics can allow 175/178 grain bullet to reach that speed from that length of barrel. It would be cool if I was wrong and please keep us posted if the dope matches the velocity given.

I'd be surprised as well if the chrono isn't off. 178's @ 2740fps made me giddy as a school girl from a 700P, with 9.5" more barrel.

 

[InkedIan]

Just noticed you are running a suppressor. My own personal experience I've seen higher then average free bore boost numbers on shorter barrels. You number might not be that far off.

I had a 17.5" barreled gun that routinely saw a 40-60 fps free bore boost when running suppressed. Same suppressor on my buddies 20" gun only increased the velocities 20 fps.

Yes Sir, SWR Omega 30. I didn't shoot it without so i'm not sure about the increase with the suppressor.

 

[newguy2k3v2]

I get around 2700@10ft with 48.4 gr out of a 16" DTA and 762sd.